Refrigerating apparatus



R. H. STARR REFRIGERATING APPARATUS Filed June 6, 1941 o M ./J f. nl! f.@R ,m Y o Z N e E o .mY/...hmm I WM n 6. 0 A 2; M021/ Z 7 MW CSZW/ W/Yw 3 M All .m ons e w. \wm T u [i m J Feb. 27, 1945.

Patented Feb., 2?, i945 UNITED l STATES PATENT OFFICE 2 Claims.

This invention relates to refrigerators, storage compartments, coolers,and the like, which are supplied with a refrigerating medium expanded orcirculated through a heat exchange unit contained therein.

It is well known that such units operate emciently when the exteriorsurfaces thereof are substantially free of ice accumulations, but due tooperating conditions, moisture content of the stored commodities andadmission of moistureladen air through door openings, the refrigeratingsurfaces of the units rapidly collect the moisture in the form of iceand they soon become so heavily coated that they cannot operateefficiently. It is then necessary to defrost the units by raisingtemperature of the refrigerating surfaces above the melting point of theice. In large storage compartments containing perishable commodities,this is a most serious problem because the necessary rise in temperatureresults in injury of the commodities, particularly frozen products. Asan alternate, the ice may be scraped from the coils, but due to theirlocation and heavy loading of the compartments they are .practicallyinaccessible. Consequently, defrosting is delayed until such time thatdefrosting becomes imperative, with the result the refrigerating unitsare operated ineiiiciently.

It is, therefore, a principal o bject of the present invention toconcentrate accumulation of the moisture at an accessible point andprevent ice formation on the heat exchange units which are depended uponin maintaining the desired refrig` erating temperatures.

It is also an object of the invention to provide a moisture accumulatoradapted to be located directly in path of the moisture-laden air whichenters the refrigerating compartment upon opening of the door thereof.

In accomplishing these and other objects of the invention, ashereinafter pointed out, I have provided improved structure, thepreferred form of which is illustrated in the accompanying drawing,wherein:

Fig. 1 is a perspective view of arefrigerator equipped in accordancewith the present invention, parts of the walls being broken away tobetter illustrate the location of the refrigerating and moisturecollecting units.

Fig. 2 is a longitudinal section through the refrigerator.

Fig. 3 is a diagrammatic perspective view of the moisture collecting andrefrigerating units, the condensing unit associated therewith, and theApplication June 6, 1941, Serial No. 396,841

valves controlling relative temperatures of the respective refrigeratingand moisture collecting units.

Referring more in detail to the drawing:

5 l designates a refrigerator such as used in storing perishablecommodities and includes insulated side walls 2 3, front and rear walls4-5, a floor 6, and top 'I forming an enclosed storage compartment 8 towhich access is had through a lo door opening 9 that is provided in thefront Wall 4, the opening being closed by a door l0.

The refrigerating compartment is provided with a primary heat exchangeor refrigerating unit II, supplied with a refrigerating medium l5 from acondensing unit I2. The unit I2 is shown as including the usualcompressor I3 having connection with the heat exchange unit II through asuction line I4, a condenser I5 connected with the discharge of thecompressor, and a receiver I6 having connection with the condenser I5,and

with the unit II, by a high pressure line Il.

The refrigerating medium is delivered to the heat exchange unit' IIunder control of a thermostatic expansion valve I 8, as in conventionalpractice, and the suction line I4 'is provided with a constant pressurevalve I 9 to cooperate with the expansion valve in maintaining asubstantially constant pressure in the heat exchange unit, the valvesbeing selectively controlled to carry a pressure necessary inmaintaining a predetermined temperature of the refrigerating surfaces 20of the heat exchange unit.

In the illustrated instance the heat exchange unit II is shown asmounted adjacent the rear wall 5 and remote from the door I0.

In storage refrigerators of the type illustrated, the commodities areclosely packed so as to reduce the air space within the refrigeratingcompartment. Upon opening of the door, to gain access to thecompartment, warm air enters the top of the door opening to replace theheavier cold air passing through the lower portion of the door opening.The warm air, upon contacting the refrigerating surfaces of the heatexchange, or reture content which condenses on the refrigerated surfacesand freezes to form an ice coating thereover. This coating rapidlybuilds up in thickness and is aggravated in accordance with thefrequency that the door is opened. Consequently, the heat exchange unitybecomes so heavily coated with ice that it is diiilcult to maintain thedesired temperature in the refrigerating compartment. It then becomesnecessary to remove the thermostatic expansion and constant pressure icetherefrom. As above pointed out, removal of frigerating, unit II,immediately loses its moisthe ice is diillcult and is likely to resultin spoilage of the stored commodities.

It is well known that escaping tendency of water vapor from the icecollected upon the heat exchange unit is greater the higher thetemperature of the ice. Hence water vapor from ice on a warmer heatexchange surface has a greater escaping tendency than on`a colder heatexchange surface.

In carrying out the present invention, I utilize this principle ineffecting transfer of ice formation from a warmer to a colder heatexchange surface, as now to be described, the surfaces Iof the heatexchange unit I being the warmer surface. In supplying the coldersurface, the compartment is provided with a secondary or smaller heatexchange unit 2| which is located at an accessible point within thestorage compartment and preferably in the direct path of the warm airwhich is admitted to the compartment upon opening of the door l0. Thesecondary unit 2l is, therefore, located in close relation with theceiling of the compartment and over the door opening 9, as shown inFigs. 1 and 2. A

In order to control formation of ice thereon. the secondary unit ispreferably located so that only the readily accessible lower surface 22thereof is subject to accumulation of the moisture in the form `of icewhich is adapted to be removed readily therefrom by a suitable scrapermanipulated through the door opening and without removal or interferencewith the stored commodities.

The secondary unit is maintained at a lower temperature than the main orprimary refrigerating unit throughrefrigerating medium supplied by apipe 23 having connection with the high -pressureline l1 and in which isinterposed a thermostatic expansion valve 24. The discharge side of thesecondary unit is connected by a similar pipe 25 With the suction lineIl and interposed therein is a constant pressure valve 26, the valves 24and 26 being set to maintain a lower temperature in the heat exchangeunit 2| than in the unit Il. For example, the valves I8` and I9 may beset to maintain a temperature of 1 F. of the primary unit and the valves24 and 26 set to maintain a temperature of 11 F. for the ice collectingsurface 22 of the secondary unit 2|. With this arrangement, the surfaces.20 of the primary refrigerating unit being of higher temperature thanthe ice accumulating surface 22 of the secondary unit 2|, the watervapor from the ice or frost tending to collect on the primary istransferred to the secondary unit. Consequently the secondary unitcollects the moisture which would normally accumulate upon the surfacesof the primary refrigerating unit and the main refrigerating unit iskept at high operating efficiency. When the frost or ice accumulatesupon the collecting surface 22, it is a simple matter to effect removalthereof since it is readily accessible through the door opening withoutdisturbing the stored com- Imodities.

Attention is also directed to the fact that when the door is opened andWarm air enters through the top of the opening, it passes directly overthe chilled surface ofthe secondary unit to effect dehydration anddeposit of the moisture on the surface 22 thereof before the air passesinto contact with the main unit.

From the foregoing it is obvious that I have provided a simple andinexpensive means for preventing accumulation of ice upon a mainrefrigerating unit of a storage compartment or the like and I haveprovided for concentration of the moisture in the form of ice at a pointwhich is readily accessible.

What I claim and desire to secure by Letters Patent is:

1. In a refrigerator having a storage compartment and a door admittingaccess to said storage compartment, a pair of cooling units havingsurfaces exposed to air in the compartment, one of said units beinglocated in said compartment within ready access through the door openingwithout removal of contents from the storage compartment, and means forsupplying a refrigerating medium to said units under such conditions asto maintain the unit that is located within said ready access throughthe door opening at a lower temperature below freezing than the otherunit, said cooler unit having a substantially flat surface area of suchsize that when free of frost and moisture it will effect condensationand freezing thereon of the moisture contained within the air insidesaid storage com partment substantially without such condensa-v tion andfreezing of the moisture occurring upon the warmer unit.

2. In a refrigerator having a storage compartment, a pair of coolingunits, one having heat exchange surfaces of different area than the heatexchange surfaces of the other unit, said units' being exposed to theair in the storage compartment, the unit of lesser heat exchange areabeing located in said compartment for ready access thereto withoutremoval of contents from the storage compartment, and means forsupplying a refrigerating medium to said units under such conditions asto maintain the unit having the smaller heat exchange area and that islocated within said ready access at a lower temperature below freezingthan the other unit, said cooler unit having a substantially fiatsurface area of such size that when free of frost or moisture it willeffect condensation and freezing thereon of moisture contained withinthe air inside said Y storage compartment substantially without suchcondensation and freezing of the moisture occurring upon the warmerunit.

RAYMOND H. STARR.

